Role of dynamic sonography in ulnar nerve entrapment at elbow

Abstract

Abstract Background High-resolution ultrasound (HRUS) is a rapidly developing technology that is gaining popularity for the evaluation of the ulnar nerve. Objective To evaluate the role of dynamic HRUS for the detection of different abnormalities of ulnar nerve entrapment at the elbow. Patients and Methods Sixty-two elbows divided into 23 elbows with symptomatic and sonographic findings (symptomatic group), 39 elbows as a control group, which were further subdivided into 24 which were clinically and sonographically free (control group), and 15 subjects as a case nonmanifest group who were clinically free, but has sonographic findings (asymptomatic UNE group), were studied. The ulnar nerve cross-sectional area (CSA) was measured at the Guyon canal, mid-forearm, and maximal swelling (MS) point around the elbow. We assessed also the flattening ratio at the elbow by measuring the widest transverse and anteroposterior diameters during elbow extension and flexion. Results There was a statistically significant difference of the cross-sectional area and flattening ratio of the ulnar nerve at the elbow during extension and flexion between the three groups (symptomatic, case nonmanifest, and healthy control elbows) (P value = 0.05). Conclusion Dynamic HRUS is a highly accurate, sensitive diagnostic modality for the ulnar nerve entrapment syndrome at the elbow.

Keywords

• Ulnar entrapment
• Ultrasonography
• Cross-sectional area
• Flattening ratio